fix(presets): raise PresetValidationError, not raw ValueError, on malformed catalog URL (#3576)

`PresetCatalog._validate_catalog_url` called `urlparse(url).hostname` without
guarding it. For a malformed authority such as an unterminated IPv6 bracket
(`https://[::1`), `urlparse(...).hostname` raises `ValueError: Invalid IPv6 URL`,
which escapes the method. Its docstring promises `PresetValidationError`, and its
callers (`preset catalog add`, `preset catalog list` reading the
`SPECKIT_PRESET_CATALOG_URL` env var / `.specify/preset-catalogs.yml`) only catch
`PresetValidationError` -- so a malformed URL crashes the CLI with a traceback
instead of a clean error message.

The shared `CatalogStackBase` (#3435), `workflows` (#3484), `bundler` (#3433) and
`IntegrationCatalog` copies already wrap this in `try/except ValueError`; the
preset validator was the remaining un-updated twin. Mirror the shared
implementation: wrap `urlparse` + `.hostname`, re-raise as
`PresetValidationError("Catalog URL is malformed: ...")`, and read the local
`hostname` in the host check.

Add a regression test mirroring `IntegrationCatalog`'s
`test_malformed_url_rejected_cleanly`; it is red before the fix (raw `ValueError`)
and green after.

Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

src/specify_cli/presets/__init__.py

@@ -2074,8 +2074,12 @@ class PresetCatalog:
         """
         from urllib.parse import urlparse
 
-        parsed = urlparse(url)
-        is_localhost = parsed.hostname in ("localhost", "127.0.0.1", "::1")
+        try:
+            parsed = urlparse(url)
+            hostname = parsed.hostname
+        except ValueError:
+            raise PresetValidationError(f"Catalog URL is malformed: {url}") from None
+        is_localhost = hostname in ("localhost", "127.0.0.1", "::1")
         if parsed.scheme != "https" and not (
             parsed.scheme == "http" and is_localhost
         ):
@@ -2086,7 +2090,7 @@ class PresetCatalog:
         # Check hostname, not netloc: netloc is truthy for host-less URLs like
         # "https://:8080" or "https://user@", so the host guarantee this error
         # promises would not actually hold. hostname is None in those cases (#3209).
-        if not parsed.hostname:
+        if not hostname:
             raise PresetValidationError(
                 "Catalog URL must be a valid URL with a host."
             )

tests/test_presets.py

@@ -1634,6 +1634,18 @@ class TestPresetCatalog:
         with pytest.raises(PresetValidationError, match="valid URL with a host"):
             catalog._validate_catalog_url(url)
 
+    def test_validate_catalog_url_malformed_rejected(self, project_dir):
+        """A malformed URL raises PresetValidationError, not a raw ValueError.
+
+        ``urlparse('https://[::1').hostname`` raises ``ValueError: Invalid IPv6
+        URL`` (unterminated bracket). Without wrapping, that leaks past callers'
+        ``except PresetValidationError`` guards and crashes the CLI. Mirrors the
+        shared ``CatalogStackBase`` (#3435) and ``IntegrationCatalog`` behaviour.
+        """
+        catalog = PresetCatalog(project_dir)
+        with pytest.raises(PresetValidationError, match="malformed"):
+            catalog._validate_catalog_url("https://[::1")
+
     def test_env_var_catalog_url(self, project_dir, monkeypatch):
         """Test catalog URL from environment variable."""
         monkeypatch.setenv("SPECKIT_PRESET_CATALOG_URL", "https://custom.example.com/catalog.json")